In general, a syringe, which includes a syringe body and a syringe needle separably installed to a front end of the syringe body, is used for directly injecting a medicament liquid into a patient in a hospital. Since most patients are contaminated with various viruses replicating in living cells as the smallest microorganisms or germs (bacteria) and specifically pathogenic bacteria harmful to a human body, which are fine single-celled organisms, a disposable syringe is mandatorily used to prevent secondary infection during injection.
However, except for solid injection requiring injection distilled water for dissolving the solid injection or diluting water-soluble injection, most of injections used in the disposable syringe are made in a liquid state and contained in glass or plastic ampoules. The injections required to be kept for a long time are made in the form of a solid so as to be dissolved in use and are contained and preserved in ampoules, so the injections are used after being mixed with injection distilled water.
Impurity powder, such as glass powder (the particle size of 10˜70 μm) or plastic powder (which is finer than the glass powder), is generated when the ampoule is opened for injection. In this state, when the medicament liquid contained in the ampoule or the mixture of the injection distilled water and the solid injection is sucked into the syringe body by using the needle (which is standardized and, in general, has an outer diameter of 652 μm) of the syringe needle, various powder or impurities generated when opening the ampoule are sucked simultaneously with the medicament liquid and the mixture, so that the powder or impurities may be injected into a human body together with the medicament liquid.
Thus, the injected impurities, in particular, glass particles of the injected impurities move along a blood vessel, thereby causing necrosis, lung granuloma, phlebitis and thrombosis. In extreme case, a cancer may be caused. That is, the injected impurities may cause many side effects.
Therefore, as shown in FIGS. 8 and 9, there has been recently proposed a filter needle including a filter 300 installed in the fixing member 220 for fixing a needle 210 in order to separably install a syringe needle 200 to a front of a syringe, so that the filter 300 may filter impurities such as a glass or plastic powder or an impurity powder generated in opening an ampoule.
In this case, if the syringe needle is not exchanged on time, the impurities attached to the filter may be injected into a patient through the syringe needle.
Practically, in the medical field, the syringe needle 200, to which the filter 300 is installed, is used to suck the medicament liquid through the syringe needle into the syringe body 100 having the cylinder 110 and the piston 120, and then, the syringe needle 200 is replaced with new one to inject the medicament liquid into a patient.
However, in this case, the medicament liquid is exposed to air so that the medicament liquid may be oxidized or infected. In addition, this sequence of woks is very complicated to medical workers and makes it difficult to rapidly treat emergency patients. Further, many disposable syringes are used even for one day and plural syringe needles are used at one time of injection, so that medical wastes are exponentially increased, thereby exerting harmful influence on environment.
Specifically, these medical syringe wastes must be treated after being separated from general medical wastes, so that the cost for treating the medical waste is increased.